Postfix: Connect; Immediate Disconnect

I'm trying to get a PHP mailing script (using PEAR) working on my web server connecting to my remote Postfix box, and each time the script executes, I get no errors in either my PHP output or my Postfix logs, but no email is sent.

The corresponding log items for the request are this:

Nov 19 10:15:34 mailer postfix/smtpd[2611]: connect from xxx-xxx-xxx-xxx.static.cloud-ips.com[xxx.xxx.xxx.xxx]
Nov 19 10:15:34 mailer postfix/smtpd[2611]: disconnect from xxx-xxx-xxx-xxx.static.cloud-ips.com[xxx.xxx.xxx.xxx]

I know my Postfix server is working correctly, since I have other applications that can send mail to it just fine (and they're relayed correctly).

I also know that this script is working since I can copy it verbatim (except for changing the location of the PEAR libraries) to another web server (on HostGator) and it connects and sends the email fine.

I wish I could get some sort of error message to give me some kinda clue as to where to go from here, but I've got no error messages: just a connection followed by an immediate disconnection. I am only having this problem trying to send mail from this specific web server.

What's causing this and what can I do to fix it?

The Web Server I'm having issues with is running Ubuntu 8.04.2 LTS (hardy).


postconf

alias_database = hash:/etc/aliases
alias_maps = hash:/etc/aliases
append_dot_mydomain = no
biff = no
broken_sasl_auth_clients = no
config_directory = /etc/postfix
inet_interfaces = all
mailbox_size_limit = 0
mydestination = test.com
myhostname = test.com
mynetworks = 66.109.25.xxx, 127.0.0.0/8
myorigin = /etc/mailname
notify_classes = bounce, 2bounce, delay, policy protocol, resource, software
readme_directory = no
recipient_delimiter = +
relayhost = 
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu)
smtpd_recipient_restrictions = permit_mynetworks,reject_unlisted_recipient,reject_non_fqdn_sender,reject_unknown_sender_domain,permit_sasl_authenticated,reject_unauth_destination,check_policy_service inet:127.0.0.1:60000,reject
smtpd_sasl_auth_enable = yes
smtpd_sasl_local_domain = test.com
smtpd_sasl_security_options = noanonymous,noplaintext
smtpd_tls_cert_file = /etc/ssl/certs/ssl-cert-snakeoil.pem
smtpd_tls_key_file = /etc/ssl/private/ssl-cert-snakeoil.key
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtpd_use_tls = yes

PHP code

<?php

  require_once('Mail.php'); // loads in PEAR Mail package; correct path

  $mailer_params['host'] = 'test.com';
  $mailer_params['port'] = 25;
  $mailer_params['auth'] = true;
  $mailer_params['username'] = '[email protected]';
  $mailer_params['password'] = 'test123';

  $mail =& Mail::factory('smtp', $mailer_params); 

  $headers = array(
    'From' => '[email protected]',
    'Reply-To' => '[email protected]',
    'Subject' => 'test'
  );

  $message = "whatever";

  $email = '[email protected]';
  try {
    $sent_ok = $mail->send($email, $headers, $message);
  } catch (Exception $e) {
    echo "Exception: ". $e->getMessage();
  }

?>

tcpdump

tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes
13:24:00.771272 IP 173-45-233-xxx.static.cloud-ips.com.58994 > mailer.xxx.com.smtp: S 4010320431:4010320431(0) win 5840 <mss 1460,sackOK,timestamp 3028083892 0,nop,wscale 5>
    0x0000:  4500 003c 469b 4000 3f06 c5c4 ad2d e92b  E..<F.@.?....-.+
    0x0010:  ad2d ebd5 e672 0019 ef08 a22f 0000 0000  .-...r...../....
    0x0020:  a002 16d0 f0df 0000 0204 05b4 0402 080a  ................
    0x0030:  b47c e4b4 0000 0000 0103 0305            .|..........
13:24:00.771272 IP mailer.xxx.com.smtp > 173-45-233-xxx.static.cloud-ips.com.58994: S 1790950084:1790950084(0) ack 4010320432 win 5792 <mss 1460,sackOK,timestamp 3171819547 3028083892,nop,wscale 5>
    0x0000:  4500 003c 0000 4000 4006 0b60 ad2d ebd5  E..<..@.@..`.-..
    0x0010:  ad2d e92b 0019 e672 6abf bac4 ef08 a230  .-.+...rj......0
    0x0020:  a012 16a0 ee50 0000 0204 05b4 0402 080a  .....P..........
    0x0030:  bd0e 201b b47c e4b4 0103 0305            .....|......
13:24:00.771272 IP 173-45-233-xxx.static.cloud-ips.com.58994 > mailer.xxx.com.smtp: . ack 1 win 183 <nop,nop,timestamp 3028083892 3171819547>
    0x0000:  4500 0034 469c 4000 3f06 c5cb ad2d e92b  E..4F.@.?....-.+
    0x0010:  ad2d ebd5 e672 0019 ef08 a230 6abf bac5  .-...r.....0j...
    0x0020:  8010 00b7 3304 0000 0101 080a b47c e4b4  ....3........|..
    0x0030:  bd0e 201b                                ....
13:24:00.799274 IP mailer.xxx.com.smtp > 173-45-233-xxx.static.cloud-ips.com.58994: P 1:45(44) ack 1 win 181 <nop,nop,timestamp 3171819554 3028083892>
    0x0000:  4500 0060 9ade 4000 4006 705d ad2d ebd5  E..`..@[email protected]].-..
    0x0010:  ad2d e92b 0019 e672 6abf bac5 ef08 a230  .-.+...rj......0
    0x0020:  8018 00b5 2faf 0000 0101 080a bd0e 2022  ..../.........."
    0x0030:  b47c e4b4 3232 3020 6d61 696c 6572 2e72  .|..220.mailer.r
    0x0040:  646e 792e 636f 6d20 4553 4d54 5020 506f  dny.com.ESMTP.Po
    0x0050:  7374 6669 7820 2855 6275 6e74 7529 0d0a  stfix.(Ubuntu)..
13:24:00.799274 IP 173-45-233-xxx.static.cloud-ips.com.58994 > mailer.xxx.com.smtp: . ack 45 win 183 <nop,nop,timestamp 3028083900 3171819554>
    0x0000:  4500 0034 469d 4000 3f06 c5ca ad2d e92b  E..4F.@.?....-.+
    0x0010:  ad2d ebd5 e672 0019 ef08 a230 6abf baf1  .-...r.....0j...
    0x0020:  8010 00b7 32c9 0000 0101 080a b47c e4bc  ....2........|..
    0x0030:  bd0e 2022                                ..."
13:24:00.799274 IP 173-45-233-xxx.static.cloud-ips.com.58994 > mailer.xxx.com.smtp: P 1:17(16) ack 45 win 183 <nop,nop,timestamp 3028083900 3171819554>
    0x0000:  4500 0044 469e 4000 3f06 c5b9 ad2d e92b  E..DF.@.?....-.+
    0x0010:  ad2d ebd5 e672 0019 ef08 a230 6abf baf1  .-...r.....0j...
    0x0020:  8018 00b7 c6ef 0000 0101 080a b47c e4bc  .............|..
    0x0030:  bd0e 2022 4548 4c4f 206c 6f63 616c 686f  ..."EHLO.localho
    0x0040:  7374 0d0a                                st..
13:24:00.799274 IP mailer.xxx.com.smtp > 173-45-233-xxx.static.cloud-ips.com.58994: . ack 17 win 181 <nop,nop,timestamp 3171819554 3028083900>
    0x0000:  4500 0034 9adf 4000 4006 7088 ad2d ebd5  E..4..@[email protected]..
    0x0010:  ad2d e92b 0019 e672 6abf baf1 ef08 a240  .-.+...rj......@
    0x0020:  8010 00b5 32bb 0000 0101 080a bd0e 2022  ....2.........."
    0x0030:  b47c e4bc                                .|..
13:24:00.799274 IP mailer.xxx.com.smtp > 173-45-233-xxx.static.cloud-ips.com.58994: P 45:213(168) ack 17 win 181 <nop,nop,timestamp 3171819554 3028083900>
    0x0000:  4500 00dc 9ae0 4000 4006 6fdf ad2d ebd5  E.....@[email protected]..
    0x0010:  ad2d e92b 0019 e672 6abf baf1 ef08 a240  .-.+...rj......@
    0x0020:  8018 00b5 302b 0000 0101 080a bd0e 2022  ....0+........."
    0x0030:  b47c e4bc 3235 302d 6d61 696c 6572 2e72  .|..250-mailer.r
    0x0040:  646e 792e 636f 6d0d 0a32 3530 2d50 4950  dny.com..250-PIP
    0x0050:  454c 494e 494e 470d 0a32 3530 2d53 495a  ELINING..250-SIZ
    0x0060:  4520 3130 3234 3030 3030 0d0a 3235 302d  E.10240000..250-
    0x0070:  5652 4659 0d0a 3235 302d 4554 524e 0d0a  VRFY..250-ETRN..
    0x0080:  3235 302d 5354 4152 5454 4c53 0d0a 3235  250-STARTTLS..25
    0x0090:  302d 4155 5448 2044 4947 4553 542d 4d44  0-AUTH.DIGEST-MD
    0x00a0:  3520 4352 414d 2d4d 4435 0d0a 3235 302d  5.CRAM-MD5..250-
    0x00b0:  454e 4841 4e43 4544 5354 4154 5553 434f  ENHANCEDSTATUSCO
    0x00c0:  4445 530d 0a32 3530 2d38 4249 544d 494d  DES..250-8BITMIM
    0x00d0:  450d 0a32 3530 2044 534e 0d0a            E..250.DSN..
13:24:00.799274 IP 173-45-233-xxx.static.cloud-ips.com.58994 > mailer.xxx.com.smtp: P 17:27(10) ack 213 win 216 <nop,nop,timestamp 3028083900 3171819554>
    0x0000:  4500 003e 469f 4000 3f06 c5be ad2d e92b  E..>F.@.?....-.+
    0x0010:  ad2d ebd5 e672 0019 ef08 a240 6abf bb99  .-...r.....@j...
    0x0020:  8018 00d8 ef85 0000 0101 080a b47c e4bc  .............|..
    0x0030:  bd0e 2022 5354 4152 5454 4c53 0d0a       ..."STARTTLS..
13:24:00.803274 IP mailer.xxx.com.smtp > 173-45-233-xxx.static.cloud-ips.com.58994: P 213:243(30) ack 27 win 181 <nop,nop,timestamp 3171819555 3028083900>
    0x0000:  4500 0052 9ae1 4000 4006 7068 ad2d ebd5  E..R..@[email protected]..
    0x0010:  ad2d e92b 0019 e672 6abf bb99 ef08 a24a  .-.+...rj......J
    0x0020:  8018 00b5 2fa1 0000 0101 080a bd0e 2023  ..../..........#
    0x0030:  b47c e4bc 3232 3020 322e 302e 3020 5265  .|..220.2.0.0.Re
    0x0040:  6164 7920 746f 2073 7461 7274 2054 4c53  ady.to.start.TLS
    0x0050:  0d0a                                     ..
13:24:00.803274 IP 173-45-233-xxx.static.cloud-ips.com.58994 > mailer.xxx.com.smtp: P 27:114(87) ack 243 win 216 <nop,nop,timestamp 3028083900 3171819555>
    0x0000:  4500 008b 46a0 4000 3f06 c570 ad2d e92b  E...F.@.?..p.-.+
    0x0010:  ad2d ebd5 e672 0019 ef08 a24a 6abf bbb7  .-...r.....Jj...
    0x0020:  8018 00d8 7178 0000 0101 080a b47c e4bc  ....qx.......|..
    0x0030:  bd0e 2023 1603 0100 5201 0000 4e03 014b  ...#....R...N..K
    0x0040:  5f33 40e4 c7ef 1dc5 f087 941d ce4a 821f  [email protected]..
    0x0050:  97d7 c6a9 c23b 6e04 c887 5772 9501 6500  .....;n...Wr..e.
    0x0060:  0026 0039 0038 0035 0016 0013 000a 0033  .&.9.8.5.......3
    0x0070:  0032 002f 0005 0004 0015 0012 0009 0014  .2./............
    0x0080:  0011 0008 0006 0003 0201 00              ...........
13:24:00.811275 IP mailer.xxx.com.smtp > 173-45-233-xxx.static.cloud-ips.com.58994: P 243:1179(936) ack 114 win 181 <nop,nop,timestamp 3171819557 3028083900>
    0x0000:  4500 03dc 9ae2 4000 4006 6cdd ad2d ebd5  E.....@[email protected]..
    0x0010:  ad2d e92b 0019 e672 6abf bbb7 ef08 a2a1  .-.+...rj.......
    0x0020:  8018 00b5 332b 0000 0101 080a bd0e 2025  ....3+.........%
    0x0030:  b47c e4bc 1603 0100 4a02 0000 4603 014b  .|......J...F..K
    0x0040:  5f33 4091 f005 3620 7505 284f 8220 37b7  [email protected].(O..7.
    0x0050:  d1ad 75e0 4528 094d 976c 6920 e0fa 2b20  ..u.E(.M.li...+.
    0x0060:  987e a3d7 9790 a336 8114 df7e 2caa f078  .~.....6...~,..x
    0x0070:  a5d3 b01d 5bd2 2da7 5b1f 7ebf e685 9eba  ....[.-.[.~.....
    0x0080:  0039 0116 0301 01b9 0b00 01b5 0001 b200  .9..............
    0x0090:  01af 3082 01ab 3082 0114 0209 009b e749  ..0...0........I
    0x00a0:  3655 ce91 0b30 0d06 092a 8648 86f7 0d01  6U...0...*.H....
    0x00b0:  0105 0500 301a 3118 3016 0603 5504 0313  ....0.1.0...U...
    0x00c0:  0f6d 6169 6c65 722e 7264 6e79 2e63 6f6d  .mailer.xxx.com
    0x00d0:  301e 170d 3039 3039 3031 3232 3335 3339  0...090901223539
    0x00e0:  5a17 0d31 3930 3833 3032 3233 3533 395a  Z..190830223539Z
    0x00f0:  301a 3118 3016 0603 5504 0313 0f6d 6169  0.1.0...U....mai
    0x0100:  6c65 722e 7264 6e79 2e63 6f6d 3081 9f30  ler.rdny.com0..0
    0x0110:  0d06 092a 8648 86f7 0d01 0101 0500 0381  ...*.H..........
    0x0120:  8d00 3081 8902 8181 00f4 1cb3 26f0 bf56  ..0.........&..V
    0x0130:  3ad5 065a 5fdb e6ee 10a6 cbee da40 1608  :..Z_........@..
    0x0140:  e2d7 e305 7d3e 1f6f ff85 9628 9bf9 5b22  ....}>.o...(..["
    0x0150:  3eae 0118 c5be 7c86 d059 d129 27e8 634f  >.....|..Y.)'.cO
    0x0160:  6cd5 c4a0 7010 766d 749d 56e7 280c a8a7  l...p.vmt.V.(...
    0x0170:  d1f7 7943 4583 6cd8 1f4a 9349 6528 b0b6  ..yCE.l..J.Ie(..
    0x0180:  3b54 ff3c da4b b84c 2bf5 a367 de07 90e8  ;T.<.K.L+..g....
    0x0190:  b68e 1a5c d5e1 537b 2d94 a6fa e44f ea6b  ...\..S{-....O.k
    0x01a0:  5d32 7b28 c2bf a942 ad02 0301 0001 300d  ]2{(...B......0.
    0x01b0:  0609 2a86 4886 f70d 0101 0505 0003 8181  ..*.H...........
    0x01c0:  0007 ce68 42a8 41b8 b84e e820 0d87 c080  ...hB.A..N......
    0x01d0:  f6cd e1f5 4ebc b007 999e 422c cfb5 c7f8  ....N.....B,....
    0x01e0:  bd09 2ff9 bc45 c1e5 d659 9f28 d6ff 3471  ../..E...Y.(..4q
    0x01f0:  fef8 1771 a266 524f 4423 e9f4 cfcc b90c  ...q.fROD#......
    0x0200:  97f0 37b7 956f f8fa 5ab8 26d3 95cf 6f55  ..7..o..Z.&...oU
    0x0210:  93ff 99f3 5b7a 5025 e8da c5fc 5e24 308c  ....[zP%....^$0.
    0x0220:  d049 461d 5437 14dc 7207 6854 8226 2b84  .IF.T7..r.hT.&+.
    0x0230:  ac02 94f3 3a28 6eb4 7cb1 e38c e147 7251  ....:(n.|....GrQ
    0x0240:  eb16 0301 018d 0c00 0189 0080 b0fe b4cf  ................
    0x0250:  d455 07e7 cc88 590d 1726 c50c a54a 9223  .U....Y..&...J.#
    0x0260:  8178 da88 aa4c 1306 bf5d 2f9e bc96 b851  .x...L...]/....Q
    0x0270:  009d 0c0d 75ad fd3b b17e 714f 3f91 5414  ....u..;.~qO?.T.
    0x0280:  44b8 3025 1ceb df72 9c4c f189 0d68 3f94  D.0%...r.L...h?.
    0x0290:  8ea4 fb76 8918 b291 1690 0199 668c 5381  ...v........f.S.
    0x02a0:  4e27 3d99 e75a 7aaf d5ec e27e faed 0118  N'=..Zz....~....
    0x02b0:  c278 2559 065c 39f6 cd49 54af c1b1 ea4a  .x%Y.\9..IT....J
    0x02c0:  f953 d0df 6daf d493 e7ba ae9b 0001 0200  .S..m...........
    0x02d0:  804e a0d2 7d52 9786 ec5a 306e 1bfc d81e  .N..}R...Z0n....
    0x02e0:  e762 6e94 c222 91b5 013f 0da6 4dfb 452a  .bn.."...?..M.E*
    0x02f0:  b931 62d4 caf7 a8ac 279d 578c b32a e7e1  .1b.....'.W..*..
    0x0300:  1e47 f159 181d fb99 b839 9854 76c1 1d87  .G.Y.....9.Tv...
    0x0310:  7796 bddc a86a d3cc 17e7 4ac0 bbc9 a1d1  w....j....J.....
    0x0320:  bc41 d42c 75d5 97f7 a17e 23aa 07fc d434  .A.,u....~#....4
    0x0330:  ee77 8633 a0e6 efc5 5257 4374 2b6b 5bd7  .w.3....RWCt+k[.
    0x0340:  ca5e 591d 7ddf 3e26 d70d 46b2 082e 6d75  .^Y.}.>&..F...mu
    0x0350:  7a00 8030 0f97 963b 61b9 b2db 9e20 06fa  z..0...;a.......
    0x0360:  3045 06b7 09ef faeb 0b65 95f2 6724 b9b7  0E.......e..g$..
    0x0370:  a7e9 b922 90d0 5c8a 7a73 65b7 1996 11ed  ..."..\.zse.....
    0x0380:  f209 fd3a eec1 2da7 a572 b272 0bd3 fb05  ...:..-..r.r....
    0x0390:  7013 5e79 37b2 e17d d59a bcca f2cb 0468  p.^y7..}.......h
    0x03a0:  5650 79ae 84c5 f602 007b e0c4 7988 b48d  VPy......{..y...
    0x03b0:  ffa9 6a5d 3b79 cca4 d33b 3660 1503 d986  ..j];y...;6`....
    0x03c0:  c553 b28e 1f01 9ca3 1e0a 3805 ac29 35c8  .S........8..)5.
    0x03d0:  467e 2f16 0301 0004 0e00 0000            F~/.........
13:24:00.851277 IP 173-45-233-xxx.static.cloud-ips.com.58994 > mailer.xxx.com.smtp: . ack 1179 win 275 <nop,nop,timestamp 3028083913 3171819557>
    0x0000:  4500 0034 46a1 4000 3f06 c5c6 ad2d e92b  E..4F.@.?....-.+
    0x0010:  ad2d ebd5 e672 0019 ef08 a2a1 6abf bf5f  .-...r......j.._
    0x0020:  8010 0113 2d7e 0000 0101 080a b47c e4c9  ....-~.......|..
    0x0030:  bd0e 2025                                ...%
13:24:00.851277 IP 173-45-233-xxx.static.cloud-ips.com.58994 > mailer.xxx.com.smtp: P 114:312(198) ack 1179 win 275 <nop,nop,timestamp 3028083913 3171819557>
    0x0000:  4500 00fa 46a2 4000 3f06 c4ff ad2d e92b  E...F.@.?....-.+
    0x0010:  ad2d ebd5 e672 0019 ef08 a2a1 6abf bf5f  .-...r......j.._
    0x0020:  8018 0113 3b49 0000 0101 080a b47c e4c9  ....;I.......|..
    0x0030:  bd0e 2025 1603 0100 8610 0000 8200 8008  ...%............
    0x0040:  ccdb 3530 85ee 026f b2da c713 e572 730f  ..50...o.....rs.
    0x0050:  b808 1641 e85b bef2 ec97 4bb2 4b3a 2371  ...A.[....K.K:#q
    0x0060:  34b9 ec27 9f8a bde4 2f5f 58a7 a6b6 4510  4..'..../_X...E.
    0x0070:  bd69 434a 1c3c 42fb bd54 de39 9052 dd9d  .iCJ.<B..T.9.R..
    0x0080:  bf0f 57a6 1f30 3ef4 1295 ec4f 75eb 06da  ..W..0>....Ou...
    0x0090:  ebe3 fcd7 2e64 cfd1 77a8 9eef e856 d197  .....d..w....V..
    0x00a0:  90de 4108 2dd6 45d8 96fb 0c2b 3185 b23e  ..A.-.E....+1..>
    0x00b0:  81f6 e931 455f 3657 78a9 793d 1b95 4f14  ...1E_6Wx.y=..O.
    0x00c0:  0301 0001 0116 0301 0030 ff4c 564d fa2b  .........0.LVM.+
    0x00d0:  5323 8a16 fd11 77dc 1b74 5385 0cd2 a2ef  S#....w..tS.....
    0x00e0:  315c 39ec c63a 8cdc 2aa4 8abd 439e 96e2  1\9..:..*...C...
    0x00f0:  0a4d 3ef7 9bbc 5726 7310                 .M>...W&s.
13:24:00.875278 IP mailer.xxx.com.smtp > 173-45-233-xxx.static.cloud-ips.com.58994: P 1179:1238(59) ack 312 win 215 <nop,nop,timestamp 3171819573 3028083913>
    0x0000:  4500 006f 9ae3 4000 4006 7049 ad2d ebd5  E..o..@[email protected]..
    0x0010:  ad2d e92b 0019 e672 6abf bf5f ef08 a367  .-.+...rj.._...g
    0x0020:  8018 00d7 2fbe 0000 0101 080a bd0e 2035  ..../..........5
    0x0030:  b47c e4c9 1403 0100 0101 1603 0100 304b  .|............0K
    0x0040:  4480 86f3 7c75 98fd 845a a0cc 7d1c 6c5a  D...|u...Z..}.lZ
    0x0050:  d742 c43e c2a1 94b6 ca03 42fb 00ff 6d27  .B.>......B...m'
    0x0060:  10b4 f834 51c1 1c12 0744 0784 11ce 82    ...4Q....D.....
13:24:00.879279 IP 173-45-233-xxx.static.cloud-ips.com.58994 > mailer.xxx.com.smtp: . ack 1238 win 275 <nop,nop,timestamp 3028083919 3171819573>
    0x0000:  4500 0034 46a3 4000 3f06 c5c4 ad2d e92b  E..4F.@.?....-.+
    0x0010:  ad2d ebd5 e672 0019 ef08 a367 6abf bf9a  .-...r.....gj...
    0x0020:  8010 0113 2c67 0000 0101 080a b47c e4cf  ....,g.......|..
    0x0030:  bd0e 2035                                ...5
13:24:00.879279 IP 173-45-233-xxx.static.cloud-ips.com.58994 > mailer.xxx.com.smtp: P 312:365(53) ack 1238 win 275 <nop,nop,timestamp 3028083919 3171819573>
    0x0000:  4500 0069 46a4 4000 3f06 c58e ad2d e92b  E..iF.@.?....-.+
    0x0010:  ad2d ebd5 e672 0019 ef08 a367 6abf bf9a  .-...r.....gj...
    0x0020:  8018 0113 711d 0000 0101 080a b47c e4cf  ....q........|..
    0x0030:  bd0e 2035 1703 0100 3029 8cbe 29be 7304  ...5....0)..).s.
    0x0040:  9f4b dca8 b447 97f6 b5c8 e7a2 c081 3c05  .K...G........<.
    0x0050:  d944 e3c6 c056 3bb3 2be8 c3f8 cfeb 7f29  .D...V;.+......)
    0x0060:  685d 0ba5 488e 0c9d 26                   h]..H...&
13:24:00.879279 IP mailer.xxx.com.smtp > 173-45-233-xxx.static.cloud-ips.com.58994: P 1238:1403(165) ack 365 win 215 <nop,nop,timestamp 3171819574 3028083919>
    0x0000:  4500 00d9 9ae4 4000 4006 6fde ad2d ebd5  E.....@[email protected]..
    0x0010:  ad2d e92b 0019 e672 6abf bf9a ef08 a39c  .-.+...rj.......
    0x0020:  8018 00d7 3028 0000 0101 080a bd0e 2036  ....0(.........6
    0x0030:  b47c e4cf 1703 0100 a059 f2fd 972c 83bb  .|.......Y...,..
    0x0040:  b0ed 652c 8460 a90f fe52 eb8a 71c5 1bfb  ..e,.`...R..q...
    0x0050:  35ad 5adf e049 9293 4906 19bb 65f2 be7c  5.Z..I..I...e..|
    0x0060:  7541 43e4 cf8f 05f4 6fab 2dbd b934 5576  uAC.....o.-..4Uv
    0x0070:  e76e 32e6 8b6e 3954 3e0f 361f 9190 0105  .n2..n9T>.6.....
    0x0080:  0662 370b 20d0 48a4 4262 b1c0 8ea4 9ed4  .b7...H.Bb......
    0x0090:  7dca a0dd b901 66a2 ba23 812f e686 fdf3  }.....f..#./....
    0x00a0:  4b84 6017 5c5b e4be b6b6 7cd0 8f35 20df  K.`.\[....|..5..
    0x00b0:  8fd6 3faf 6557 002a f7dc 1ada af51 8a7f  ..?.eW.*.....Q..
    0x00c0:  6b37 fee6 4e5b aa85 1470 18b3 bf43 f594  k7..N[...p...C..
    0x00d0:  046a c7fd e8d7 3a2c 48                   .j....:,H
13:24:00.879279 IP 173-45-233-xxx.static.cloud-ips.com.58994 > mailer.xxx.com.smtp: P 365:418(53) ack 1403 win 333 <nop,nop,timestamp 3028083920 3171819574>
    0x0000:  4500 0069 46a5 4000 3f06 c58d ad2d e92b  E..iF.@.?....-.+
    0x0010:  ad2d ebd5 e672 0019 ef08 a39c 6abf c03f  .-...r......j..?
    0x0020:  8018 014d 29cc 0000 0101 080a b47c e4d0  ...M)........|..
    0x0030:  bd0e 2036 1703 0100 3074 085e cf4b 984b  ...6....0t.^.K.K
    0x0040:  2560 362f a49c 10e5 18f2 5ab5 076c 09ab  %`6/......Z..l..
    0x0050:  b570 734f 622e ae8c 366d f7bb 910a 5e95  .psOb...6m....^.
    0x0060:  5d02 a415 f464 594a 0d                   ]....dYJ.
13:24:00.879279 IP mailer.xxx.com.smtp > 173-45-233-xxx.static.cloud-ips.com.58994: P 1403:1456(53) ack 418 win 215 <nop,nop,timestamp 3171819574 3028083920>
    0x0000:  4500 0069 9ae5 4000 4006 704d ad2d ebd5  E..i..@[email protected]..
    0x0010:  ad2d e92b 0019 e672 6abf c03f ef08 a3d1  .-.+...rj..?....
    0x0020:  8018 00d7 2fb8 0000 0101 080a bd0e 2036  ..../..........6
    0x0030:  b47c e4d0 1703 0100 3043 6cf7 3196 f6ef  .|......0Cl.1...
    0x0040:  e759 8309 3636 0ea0 e215 bb9e 6399 7cb3  .Y..66......c.|.
    0x0050:  bfaa 9251 f1d4 eae0 02fb 6199 349a 92e1  ...Q......a.4...
    0x0060:  ff13 6096 18cb a366 da                   ..`....f.
13:24:00.895279 IP 173-45-233-xxx.static.cloud-ips.com.58994 > mailer.xxx.com.smtp: P 418:487(69) ack 1456 win 333 <nop,nop,timestamp 3028083924 3171819574>
    0x0000:  4500 0079 46a6 4000 3f06 c57c ad2d e92b  E..yF.@.?..|.-.+
    0x0010:  ad2d ebd5 e672 0019 ef08 a3d1 6abf c074  .-...r......j..t
    0x0020:  8018 014d f037 0000 0101 080a b47c e4d4  ...M.7.......|..
    0x0030:  bd0e 2036 1703 0100 4077 9651 35a8 076e  [email protected]
    0x0040:  052b 15a0 c757 891a 57c6 5aca 705d 7de9  .+...W..W.Z.p]}.
    0x0050:  f02d 6ba7 8bce 9304 48e7 0f7f 0383 18a3  .-k.....H.......
    0x0060:  ae04 e8fa 9e3f 1539 12d1 9a97 5dad 2980  .....?.9....].).
    0x0070:  4c92 b42d 59d3 1d90 1c                   L..-Y....
13:24:00.895279 IP mailer.xxx.com.smtp > 173-45-233-xxx.static.cloud-ips.com.58994: P 1456:1493(37) ack 487 win 215 <nop,nop,timestamp 3171819578 3028083924>
    0x0000:  4500 0059 9ae6 4000 4006 705c ad2d ebd5  E..Y..@[email protected]\.-..
    0x0010:  ad2d e92b 0019 e672 6abf c074 ef08 a416  .-.+...rj..t....
    0x0020:  8018 00d7 2fa8 0000 0101 080a bd0e 203a  ..../..........:
    0x0030:  b47c e4d4 1703 0100 2094 10b1 8bd5 a7a9  .|..............
    0x0040:  5b97 9a41 0eae 5874 8b94 f69b b658 69a4  [..A..Xt.....Xi.
    0x0050:  254e 19f1 d47d e608 6b                   %N...}..k
13:24:00.899280 IP 173-45-233-xxx.static.cloud-ips.com.58994 > mailer.xxx.com.smtp: P 487:540(53) ack 1493 win 333 <nop,nop,timestamp 3028083924 3171819578>
    0x0000:  4500 0069 46a7 4000 3f06 c58b ad2d e92b  E..iF.@.?....-.+
    0x0010:  ad2d ebd5 e672 0019 ef08 a416 6abf c099  .-...r......j...
    0x0020:  8018 014d 5282 0000 0101 080a b47c e4d4  ...MR........|..
    0x0030:  bd0e 203a 1703 0100 304d e9aa 5e23 0557  ...:....0M..^#.W
    0x0040:  81fd 8d07 f103 bbb7 8468 ee3d dce0 0956  .........h.=...V
    0x0050:  eb8f b10e a7e2 07ee 848e 64aa c011 cdc3  ..........d.....
    0x0060:  96bc 5bba 634b d361 41                   ..[.cK.aA
13:24:00.903280 IP mailer.xxx.com.smtp > 173-45-233-xxx.static.cloud-ips.com.58994: P 1493:1530(37) ack 540 win 215 <nop,nop,timestamp 3171819580 3028083924>
    0x0000:  4500 0059 9ae7 4000 4006 705b ad2d ebd5  E..Y..@[email protected][.-..
    0x0010:  ad2d e92b 0019 e672 6abf c099 ef08 a44b  .-.+...rj......K
    0x0020:  8018 00d7 2fa8 0000 0101 080a bd0e 203c  ..../..........<
    0x0030:  b47c e4d4 1703 0100 20d6 5aae 1e65 8537  .|........Z..e.7
    0x0040:  975d d8f0 f76d aefe 6459 f51b 1b1c 292b  .]...m..dY....)+
    0x0050:  0f5a 285f 2091 b55c 74                   .Z(_...\t
13:24:00.903280 IP 173-45-233-xxx.static.cloud-ips.com.58994 > mailer.xxx.com.smtp: P 540:593(53) ack 1530 win 333 <nop,nop,timestamp 3028083926 3171819580>
    0x0000:  4500 0069 46a8 4000 3f06 c58a ad2d e92b  E..iF.@.?....-.+
    0x0010:  ad2d ebd5 e672 0019 ef08 a44b 6abf c0be  .-...r.....Kj...
    0x0020:  8018 014d a614 0000 0101 080a b47c e4d6  ...M.........|..
    0x0030:  bd0e 203c 1703 0100 3067 4f03 ddcf 7dd6  ...<....0gO...}.
    0x0040:  e8e7 a29f e0c0 b4c5 33f0 a7e7 f9c5 e777  ........3......w
    0x0050:  3f8e 16f2 a543 7be6 c6a2 ec4f 617e a3e8  ?....C{....Oa~..
    0x0060:  8cc5 40bc e0ab a95b 2b                   ..@....[+
13:24:00.903280 IP mailer.xxx.com.smtp > 173-45-233-xxx.static.cloud-ips.com.58994: P 1530:1599(69) ack 593 win 215 <nop,nop,timestamp 3171819580 3028083926>
    0x0000:  4500 0079 9ae8 4000 4006 703a ad2d ebd5  E..y..@[email protected]:.-..
    0x0010:  ad2d e92b 0019 e672 6abf c0be ef08 a480  .-.+...rj.......
    0x0020:  8018 00d7 2fc8 0000 0101 080a bd0e 203c  ..../..........<
    0x0030:  b47c e4d6 1703 0100 40b3 584e 9cc9 32df  .|[email protected].
    0x0040:  e8ed 632f 9f99 3218 802d 895a 94b0 77bb  ..c/..2..-.Z..w.
    0x0050:  ff59 0d35 2fd9 ffe5 72a3 3897 8eb3 9391  .Y.5/...r.8.....
    0x0060:  c9ea 183d b36e 8a07 cfbf c547 b8ce f037  ...=.n.....G...7
    0x0070:  468a 214f 6c38 2277 08                   F.!Ol8"w.
13:24:00.903280 IP 173-45-233-xxx.static.cloud-ips.com.58994 > mailer.xxx.com.smtp: P 593:902(309) ack 1599 win 333 <nop,nop,timestamp 3028083926 3171819580>
    0x0000:  4500 0169 46a9 4000 3f06 c489 ad2d e92b  E..iF.@.?....-.+
    0x0010:  ad2d ebd5 e672 0019 ef08 a480 6abf c103  .-...r......j...
    0x0020:  8018 014d 8dd1 0000 0101 080a b47c e4d6  ...M.........|..
    0x0030:  bd0e 203c 1703 0101 307b b4db 002a 5040  ...<....0{...*P@
    0x0040:  761a 6738 9d40 0e8a e925 2c64 de46 c157  v.g8.@...%,d.F.W
    0x0050:  1d30 30dc 5861 edf0 d47b 5c62 bb94 a05e  .00.Xa...{\b...^
    0x0060:  f0e6 4e02 4ffd 1001 c6a2 4c08 907a d62f  ..N.O.....L..z./
    0x0070:  fb03 9059 1f41 cd37 7953 a2ea 67c8 e785  ...Y.A.7yS..g...
    0x0080:  9437 cb32 5052 f46b b134 0db8 1873 b3a6  .7.2PR.k.4...s..
    0x0090:  d404 0e17 fc65 865e 31ab f5aa a793 4b0e  .....e.^1.....K.
    0x00a0:  5264 deb1 7d35 ccb0 4691 8d44 787f 7e82  Rd..}5..F..Dx.~.
    0x00b0:  d731 5aef 5176 4ec5 4afe f14a af28 3fcf  .1Z.QvN.J..J.(?.
    0x00c0:  7da5 399e f6b5 c450 8cca 7439 e690 429c  }.9....P..t9..B.
    0x00d0:  54b2 51b5 a28e 8293 3da8 6cc6 fcb5 179c  T.Q.....=.l.....
    0x00e0:  1e11 58da 50c9 ca8f e217 4b8a 9dd4 bf98  ..X.P.....K.....
    0x00f0:  96f3 80b8 264a ad1a 89a7 d29b b284 7346  ....&J........sF
    0x0100:  fdf8 c168 f05c 12da f7a9 a14b e55e fc97  ...h.\.....K.^..
    0x0110:  01c5 d999 a1ea ee37 5306 4b65 0373 497a  .......7S.Ke.sIz
    0x0120:  6f25 cbe0 6a46 cacb 0da5 bca0 51a9 43d3  o%..jF......Q.C.
    0x0130:  fb5f 4a60 d0fb 21fc 021e 82f6 791f 2d8b  ._J`..!.....y.-.
    0x0140:  5011 94d2 6183 9956 5198 33d3 8a5c c6dd  P...a..VQ.3..\..
    0x0150:  722f 18cc 3980 1281 6192 6f5c b1d0 bebe  r/..9...a.o\....
    0x0160:  f854 f7dd b508 8732 8b                   .T.....2.
13:24:00.927281 IP mailer.xxx.com.smtp > 173-45-233-xxx.static.cloud-ips.com.58994: P 1599:1668(69) ack 902 win 248 <nop,nop,timestamp 3171819586 3028083926>
    0x0000:  4500 0079 9ae9 4000 4006 7039 ad2d ebd5  E..y..@[email protected]..
    0x0010:  ad2d e92b 0019 e672 6abf c103 ef08 a5b5  .-.+...rj.......
    0x0020:  8018 00f8 2fc8 0000 0101 080a bd0e 2042  ..../..........B
    0x0030:  b47c e4d6 1703 0100 407b 07ad 999f 67bf  .|......@{....g.
    0x0040:  9447 fb2d 0c0a 0378 c513 a982 4c09 fd7a  .G.-...x....L..z
    0x0050:  51b3 728e 3687 2661 0cbb b554 f227 4f54  Q.r.6.&a...T.'OT
    0x0060:  8b3b 65aa 34ba b71a 9a2e 6c23 54f4 8917  .;e.4.....l#T...
    0x0070:  9f64 1fef 6de8 692f a8                   .d..m.i/.
13:24:00.927281 IP 173-45-233-xxx.static.cloud-ips.com.58994 > mailer.xxx.com.smtp: P 902:955(53) ack 1668 win 333 <nop,nop,timestamp 3028083932 3171819586>
    0x0000:  4500 0069 46aa 4000 3f06 c588 ad2d e92b  E..iF.@.?....-.+
    0x0010:  ad2d ebd5 e672 0019 ef08 a5b5 6abf c148  .-...r......j..H
    0x0020:  8018 014d 72ee 0000 0101 080a b47c e4dc  ...Mr........|..
    0x0030:  bd0e 2042 1703 0100 309d d4aa d0a4 4d47  ...B....0.....MG
    0x0040:  edea 624a 2df2 8ac8 99e4 65c0 724c 17f0  ..bJ-.....e.rL..
    0x0050:  4745 481f 7906 d143 a6c0 75e9 767e 2b9b  GEH.y..C..u.v~+.
    0x0060:  d7b9 228f e937 30ef 3a                   .."..70.:
13:24:00.927281 IP mailer.xxx.com.smtp > 173-45-233-xxx.static.cloud-ips.com.58994: P 1668:1721(53) ack 955 win 248 <nop,nop,timestamp 3171819586 3028083932>
    0x0000:  4500 0069 9aea 4000 4006 7048 ad2d ebd5  E..i..@[email protected]..
    0x0010:  ad2d e92b 0019 e672 6abf c148 ef08 a5ea  .-.+...rj..H....
    0x0020:  8018 00f8 2fb8 0000 0101 080a bd0e 2042  ..../..........B
    0x0030:  b47c e4dc 1703 0100 30eb 7d04 85a1 2411  .|......0.}...$.
    0x0040:  eb9f 9abc 068b d36d 1c21 1e1e 4857 bce7  .......m.!..HW..
    0x0050:  eb7e 5980 f3b4 61c7 bd76 00bc 3165 a980  .~Y...a..v..1e..
    0x0060:  1ca3 5c67 a502 3b73 ea                   ..\g..;s.
13:24:00.927281 IP mailer.xxx.com.smtp > 173-45-233-xxx.static.cloud-ips.com.58994: F 1721:1721(0) ack 955 win 248 <nop,nop,timestamp 3171819586 3028083932>
    0x0000:  4500 0034 9aeb 4000 4006 707c ad2d ebd5  E..4..@[email protected]|.-..
    0x0010:  ad2d e92b 0019 e672 6abf c17d ef08 a5ea  .-.+...rj..}....
    0x0020:  8011 00f8 2801 0000 0101 080a bd0e 2042  ....(..........B
    0x0030:  b47c e4dc                                .|..
13:24:00.927281 IP 173-45-233-xxx.static.cloud-ips.com.58994 > mailer.xxx.com.smtp: P 955:992(37) ack 1721 win 333 <nop,nop,timestamp 3028083932 3171819586>
    0x0000:  4500 0059 46ab 4000 3f06 c597 ad2d e92b  E..YF.@.?....-.+
    0x0010:  ad2d ebd5 e672 0019 ef08 a5ea 6abf c17d  .-...r......j..}
    0x0020:  8018 014d e21e 0000 0101 080a b47c e4dc  ...M.........|..
    0x0030:  bd0e 2042 1503 0100 2067 29a7 644c ff8f  ...B.....g).dL..
    0x0040:  5abc 3b17 f77b f381 7ab7 d718 0e2a 535b  Z.;..{..z....*S[
    0x0050:  91a0 6a11 0ea8 35f2 0d                   ..j...5..
13:24:00.927281 IP mailer.xxx.com.smtp > 173-45-233-xxx.static.cloud-ips.com.58994: R 1790951805:1790951805(0) win 0
    0x0000:  4500 0028 0000 4000 4006 0b74 ad2d ebd5  E..(..@[email protected]..
    0x0010:  ad2d e92b 0019 e672 6abf c17d 0000 0000  .-.+...rj..}....
    0x0020:  5004 0000 6dbb 0000                      P...m...
13:24:00.927281 IP 173-45-233-xxx.static.cloud-ips.com.58994 > mailer.xxx.com.smtp: F 992:992(0) ac

tcpdump -s0 -X -i eth0 port 25 and host YOUR_CLIENTPHP_IP_HERE